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// Copyright 2019 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.actionsketch;
import com.google.auto.value.AutoValue;
import com.google.devtools.build.skyframe.SkyValue;
import com.google.protobuf.ByteString;
import java.math.BigInteger;
import java.nio.ByteBuffer;
import javax.annotation.Nullable;
/**
* An {@link ActionSketch} encodes a transitive hash of an action sufficient to associate with it
* the result of executing the action. Therefore, this must include a hash on some upper bound of
* all transitively consumed input files, as well as a transitive hash of all action keys.
*/
@AutoValue
public abstract class ActionSketch implements SkyValue {
public static final int BIGINTEGER_ENCODED_LENGTH = /*length=*/ 1 + /*payload=*/ 39;
public static final int MAX_BYTES = /*hashes=*/ 2 * BIGINTEGER_ENCODED_LENGTH;
private static final ActionSketch NULL_SKETCH =
ActionSketch.builder()
.setTransitiveSourceHash(null)
.setTransitiveActionLookupHash(null)
.autoBuild();
@Nullable
public abstract BigInteger transitiveSourceHash();
@Nullable
public abstract BigInteger transitiveActionLookupHash();
public static Builder builder() {
return new AutoValue_ActionSketch.Builder();
}
public abstract Builder toBuilder();
/** A builder for {@link ActionSketch}. */
@AutoValue.Builder
public abstract static class Builder {
public abstract Builder setTransitiveSourceHash(BigInteger transitiveSourceHash);
public abstract Builder setTransitiveActionLookupHash(BigInteger transitiveActionLookupHash);
@Nullable
abstract BigInteger transitiveSourceHash();
@Nullable
abstract BigInteger transitiveActionLookupHash();
abstract ActionSketch autoBuild();
public final ActionSketch build() {
return transitiveSourceHash() == null && transitiveActionLookupHash() == null
? NULL_SKETCH
: autoBuild();
}
}
public final ByteString toBytes() {
ByteBuffer buffer = ByteBuffer.allocate(MAX_BYTES);
writeTo(buffer);
return ByteString.copyFrom(buffer.array(), 0, buffer.position());
}
public final void writeTo(ByteBuffer buffer) {
writeNextValue(transitiveSourceHash(), buffer);
writeNextValue(transitiveActionLookupHash(), buffer);
}
public static void writeNextValue(@Nullable BigInteger value, ByteBuffer buffer) {
if (value == null) {
buffer.put((byte) -1);
} else {
byte[] bytes = value.toByteArray();
buffer.put((byte) bytes.length).put(bytes);
}
}
public static ActionSketch fromBytes(ByteString inputBytes) {
return fromByteBuffer(inputBytes.asReadOnlyByteBuffer());
}
public static ActionSketch fromByteBuffer(ByteBuffer buffer) {
Builder builder =
builder()
.setTransitiveSourceHash(readNextValue(buffer))
.setTransitiveActionLookupHash(readNextValue(buffer));
return builder.build();
}
@Nullable
public static BigInteger readNextValue(ByteBuffer buffer) {
byte length = buffer.get();
if (length < 0) {
return null;
}
byte[] val = new byte[length];
buffer.get(val);
return new BigInteger(val);
}
}